JP2564212B2 - Engine with balancer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balancer engine.

[0002]

2. Description of the Related Art As a conventional technology for a balancer engine,
There is a crankcase in which a crankshaft and a balancer shaft are horizontally arranged in parallel.

In this prior art, in order to reinforce the crankcase, ribs may be formed on the lateral wall of the crankcase.

[0004]

The above-mentioned conventional techniques have the following problems. The lateral width of the crankcase is wide enough to accommodate the balancer shaft, and when ribs are formed on the lateral wall of the crankcase, the ribs project laterally, so that the lateral width of the crankcase becomes wider. For this reason,
The engine becomes larger.

An object of the present invention is to prevent the rib from protruding laterally.

[0006]

As shown in FIG. 1 (B), the present invention provides an engine with a balancer in which a crankshaft 2 and a balancer shaft 3.3 are installed in a crankcase 1 in a laterally parallel manner. The following features are provided.

As shown in FIG. 1B, front and rear adjoining portions 7 and 8 of a lateral wall 4 of the crankcase 1 facing a balancer weight 5 of the balancer shaft 3 are adjacent front and rear portions 7 and 8 of the crankcase 1. A rib 9 having the facing portion 6 as a top is formed between the adjacent front and rear portions 7 and 8 by retreating inward, and a balancer weight passing space 10 is formed in the rib 9.
And the rotating balancer weight 5 passes through the balancer weight passage space 10.

[0008]

As shown in FIG. 1 (B), front and rear adjacent portions 7 and 8 of the facing portion 6 of the lateral wall 4 of the crankcase 1 facing the balancer weight 5 of the balancer shaft 3 are retracted to the inside of the crankcase 1. Since the rib 9 having the abutting portion 6 as the top is formed between the front and rear adjacent portions 7 and 8, the rib 9 is formed.
Does not overhang. Therefore, the lateral width of the crankcase 1 can be kept small, and the engine can be downsized.

As shown in FIG. 1 (B), the balancer weight passage space 10 is held in the ribs 9 so that the rotating balancer weight 5 passes through the balancer weight passage space 10. The balancer weight 5 does not interfere with the rib 9.

[0010]

INDUSTRIAL APPLICABILITY Of the lateral wall of the crankcase, the front and rear adjacent portions of the opposed portion of the lateral wall of the balancer shaft facing the balancer weight are retracted to the inside of the crankcase, and the rib having the opposed portion as the top between the adjacent front and rear portions. Since the ribs are formed, the ribs do not project laterally. Therefore, the width of the crankcase can be kept small and the engine can be downsized.

[0011]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a view for explaining an engine with a balancer according to an embodiment of the present invention, and FIG. 1 (A) is a vertical cross-sectional front view of the lower part of the engine with a crank angle of 0 °. FIG. 1 (B) is FIG.
FIG. 9A is a sectional view taken along line B-B of FIG.

In FIG. 1, reference numeral 11 indicates an in-line two-cylinder engine. As shown in FIG. 1 (A), the engine 11 is configured by integrally forming a crankcase 1 on the lower side of a cylinder block 12 and assembling an oil pan 13 on the lower side of the crankcase 1. In addition, FIG. 1 (B)
As shown in FIG. 3, a crankshaft 2 and two balancer shafts 3 and 3 are horizontally installed in a crankcase 1.

The crankshaft 2 is as follows. As shown in FIG. 1B, two pairs of crank arms 14.1 are provided.
Both crankpins 15 installed between the tip of 4
The angle of 15 is 360 °. Two pairs of counterweights 16 are provided on the opposite sides of the two pairs of crank arms 14. Adjacent center side counter weight 16.1
6 is integrated. A crank gear 17 and a crank pulley 18 are fitted to the front end of the crank shaft 2. A flywheel 19 is attached to the rear end of the crankshaft 2. A dynamo 20 is arranged in the flywheel 19.

A balancer weight 5 is attached to each of the balancer shafts 3 at two positions, and a balancer gear 21 is fitted to the front end of each balancer shaft 3. Each balancer gear 21 is meshed with the crank gear 17. The crank gear 17 and the balancer gear 21 have the same gear ratio. As shown in FIG. 1 (A), the crankshaft 2 rotates clockwise, and each balancer shaft 3 rotates counterclockwise at the same speed as the crankshaft 2.

The mounting state of the crankshaft 2 and each balancer shaft 3 on the crankcase 1 is as follows. FIG.
As shown in (B), the front journal portion 24 of the crankshaft 2 is inserted through the front wall central bearing hole 23 at the center of the front wall 22 of the crankcase 1 to bear the same. Front wall left and right bearing portions 25 at the left and right positions of the front wall 22 of the crankcase 1
Each front side journal portion 26 of each balancer shaft 3 is inserted into the shaft 25, and the bearing is supported by a retaining nut 27.

A shaft insertion hole 28 is formed in the rear wall of the crankcase 1, and this is covered with a removable bearing lid 29. A bearing case 30 is attached to the inside of the central portion of the bearing lid 29, and a rear side journal portion 31 of the crankshaft 2 is inserted into the bearing case 30 to bear the same. The bearing lid 29 is located inside the left and right positions of the bearing lid 29.
Attached to the rear journal part 3 of each balancer shaft 3.
3 is inserted and is bearing.

In this engine 11, the crankcase 1
Of the lateral wall 4 of the crankcase 1 in order to reinforce the counter part 6 that faces the balancer weight 5 of the balancer shaft 3.
The front and rear adjacent portions 7 and 8 are retracted to the inside of the crankcase 1, and a rib 9 having a U-shaped cross section with the facing portion 6 as the top is formed between the front and rear adjacent portions 7 and 8. The rib 9 is vertically long as shown in FIG. Also,
In order to prevent the rotating balancer weight 5 from interfering with the rib 9, the balancer weight passing space 10 is held in the rib 9 so that the rotating balancer weight 5 passes through the balancer weight passing space 10.

In this engine 11, as shown in FIG. 1 (A), the lower peripheral surface portion 34 of the counterweight 16 is formed in an arc shape, and both lateral peripheral surface portions 35 of the lower peripheral surface portion 34 are lower peripheral surface portions 34. It has a flat shape that is retracted inward. Further, the lower peripheral surface portion 36 of the balancer weight 5 is formed in an arc shape, but both lateral peripheral surface portions 37 of the balancer weight 5 are flattened inwardly with respect to the lower peripheral surface portion 36. Then, the crankshaft 2 and each balancer shaft 3 are brought closer to each other by the amount of the retreat. Due to these approaches, the width of the crankcase 1 can be narrowed.

As shown in FIG. 1 (A), an interference avoidance gap 38.3 is formed between the horizontal peripheral surface portion 35 of the counterweight 16 and the horizontal peripheral surface portion 37 of each balancer weight 5 when the shaft is inserted.
8 are held respectively. After inserting each balancer shaft 3 into the crankcase 1 through the shaft insertion hole 28 and then inserting the crankshaft 2 in the same manner, the horizontal peripheral surface portion 35 of the counterweight 16 and the horizontal peripheral surface portion 37 of the balancer weight 5 are inserted.
That is, the interference avoidance gap 38 prevents mutual interference. Reference numeral 39 is a lubricating oil supply pump,
Reference numeral 40 is a governor device.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an engine with a balancer according to an embodiment of the present invention. FIG. 1 (A) is a vertical cross-sectional front view of the lower part of the engine with a crank angle of 0 °. FIG. 1B is a sectional view taken along line BB of FIG.
It has a crank angle of 90 °.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Crank case, 2 ... Crank shaft, 3 ... Balancer shaft, 4 ... 1 lateral wall, 5 ... Balancer weight, 6 ... Opposing part, 7 ... 6 front adjacent part, 8 ... 6 rear adjacent part, 9 ... Rib 10 ... Balancer weight passage space.

Claims (1)

(57) [Claims] 1. A crankshaft (2) in a crankcase (1)
And a balancer shaft (3), (3) are installed in a laterally parallel manner, in a balancer engine, in the lateral wall (4) of the crankcase (1), the balancer weight (5) of the balancer shaft (3) Front and rear adjacent parts (7) of the facing part (6) facing the
(8) is retracted to the inside of the crankcase (1), and a rib (9) is formed between the front and rear adjacent parts (7) and (8) with the facing part (6) as the top. The balancer weight passing space (10) is retained in the rib (9), and the rotating balancer weight (5) is configured to pass through the balancer weight passing space (10). .